A power converter of a reluctance motor with two main switches per phase is a unipolar power converter, which supplies unipolar electric current to the switched reluctance motor. In a severe environment, the power converter of switched reluctance motor is liable to break down. In contrast, with a power converter of a reluctance motor with two main switches per phase, the motor magnetic circuit and the system circuit in the switched reluctance motor system are independent from each other, therefore, when any faults happen to the switched reluctance motor system, fault tolerant measures can be taken to ensure that the switched reluctance motor system operates reliably in a severe environment. Freewheeling diode is one of the important components of the power converter of a switched reluctance motor as well as an important assurance for phase commutation of the switched reluctance motor and current commutation of the main switches. At present, the existing power converters of reluctance motor with two main switches per phase do not have fault detecting and fault locating functions for freewheeling diode, as a result, when any faults happen to the freewheeling diode of the power converter, the system can not determine the fault type of the freewheeling diode and can not locate the fault. Whereas, detecting and locating faults of freewheeling diodes of the power converter of a switched reluctance motor timely and reliably is an assurance for fault-tolerant operation of the switched reluctance motor system.